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This paper reports on swift heavy ion (SHI) induced defects that were correlated to the color tuning in Dy3+ activated Y2O3 nanocrystals for possible application in white light emitting diodes and high energy dosimetry. The optimum concentration of trivalent dysprosium (Dy3+) doped with yttrium oxide (Y2O3) was prepared by the solution combustion technique. X-ray diffraction results revealed that the obtained powder material is a single phase body center cubic structure. The transmission electron microscopy images revealed that the particles were irregular shape with an average size of 37 nm. The composition of the synthesized materials were confirmed by Fourier transformed infra-red transmittance and Raman spectroscopy. The Dy3+ doped Y2O3 upon illumination with ultraviolet light showed the characteristic greenish yellow emission of Dy3+. This greenish yellow emission was enhanced when it was exposed to 100 MeV swift Si8+ ions and the ratio between yellow and blue emission could be tuned. This is ascribed to the SHI induced electrons/holes traps and the energy transfer between the electron/hole recombination centers and activator states in the host. The life time enhancement was found to be 931.55 μs and the photometric characterization showed that SHI influences the phosphor material to achieve pure white emission for light emitting diode applications at and beyond a fluence of 1 × 1011 ions cm−2. Thermoluminescence (TL) glow curves of 100 MeV Si8+ ion irradiated samples showed three glows with peaks at 408, 467and 592 K. The prominent peak (408 K) intensity increased upto a fluence of 1 × 1011 ions cm−2. TL trapping parameters were calculated using glow curve deconvolution (GCD) technique and the obtained results are discussed in detail.

Combustion synthesized nanocrystalline holmium (Ho) doped yttrium oxide (Y2O3) was irradiated with gamma (γ) rays, 100 MeV silicon (Si8+) and 150 MeV gold (Au9+) ions to investigate the thermoluminescent (TL) properties for dosimeter applications. No changes were observed in the crystal structure of the material even after it was exposed to the high energy ion beams. The sizes of the crystallites, however, decreased. The TL glow curves of the γ-irradiated samples showed a prominent peak at 419 K with a shoulder at 493 K. TL glow curves for the Si8+ and Au9+ ion irradiated samples showed maximum peaks centred at 407 K, 660 K and 465, 509 and 640 K. The TL glow curve peak intensity of the γ-irradiated samples increased upto a 3 kGy dose and then it decreased with a further increase in the dose but the position of the glow curve peak's temperature remained constant. The TL intensity of the Si8+ and Au9+ ions irradiated samples increased upto 5 × 1010 ions cm−2 of the fluence and then it decreased with a further increase in ion fluence. The glow curves' shapes were different from that of the gamma irradiated samples, because of different TL mechanisms involved. The TL curves were deconvoluted to calculate the kinetic parameters. The activation energy and the frequency factor are in the range of 0.90 eV–1.40 eV and 7.21 × 109 − 5.83 × 1014 s−1, respectively. The synthesized material exhibited longer TL lifetimes under the 150 MeV Au9+ ions to that of the 100 MeV Si8+ and gamma irradiated samples. The results demonstrated that Y2O3:Ho3+ possesses a high resistance to defect formation even at high electronic energy depositions. After swift heavy ion (SHI) irradiation the samples exhibited radiation resistance.

Y2O3 and Y2O3:Tb3+ powders, synthesized via the solution combustion method, were studied in order to determine the effect of 100 MeV swift Ni8+ ions on the photoluminescence (PL), thermoluminescence (TL) and swift ion beam induced defects. Synthesized materials were characterized by X-ray powder diffraction, electron spin resonance, PL intensity, decay measurements and TL. Cubic structures were observed in both the pristine and ion irradiated materials. The ion irradiated materials exhibited smaller crystallite sizes than that of the pristine material. PL peaks in the visible region were identified at 485, 542, 582 and 621 nm due to the 5D4 → 7F3,4,5,6 transition of Tb3+. The PL intensity showed an increase up to 3 × 1010 ions cm−2 and then a significant decrease with a further increase in the ion fluence. The recorded time resolved PL at an ion irradiated fluence of 3 × 1010 ions cm−2, exhibited an increase in the life time of the material. TL glow curves were obtained for the samples irradiated with a swift Ni8+ ion beam. These glow curves showed a peak at 518 K with a shoulder peak at 473 K and its intensity linearly increased upto a fluence of 1 × 1011 ions cm−2. Whereas, the undoped sample showed peaks at 421 and 662 K and its intensity sub-linearly increased upto a fluence of 1 × 1011 ions −2. TL efficiency values of the Y2O3:Tb3+ sample, irradiated by a 100 MeV Ni8+ ion beam, have been measured relative to the undoped Y2O3 sample and were found to be 1.34. The Tb3+ doped sample exhibited a less fading effect under the swift heavy ion beam.

Thermoluminescence (TL) properties of 60Co gamma irradiated Sm3+ doped Y2O3 nanophosphors were investigated for possible application for high dose gamma radiation dosimetry. Sm3+ doped Y2O3 nanophosphors were synthesized by the solution combustion method. The crystalline phase was analyzed with X-ray diffraction and an average crystallite size was found to be ~20–33 nm. TL glow curves of gamma irradiated Sm3+ doped Y2O3 nanophosphors were recorded. The TL glow curves showed a prominent glow peak at ~400 K, a smaller intensity peak at 510 K and a very weak intensity glow peak at ~640 K. These glow peaks were ascribed to host defects and Sm3+ characteristic emission. The effect of Sm3+ concentration on the TL was explored and the optimum Sm3+ concentration was found to be 0.1 mol%. The number of overlapping TL glow peaks were identified from the broad TL glow curve by the thermal cleaning method. The kinetic parameters were obtained by the glow curve deconvolutions method using the general order kinetics expression. The variation of the TL intensity with dose, the effect of heating rates, repeatability and the fading effects of gamma irradiated Sm3+ doped Y2O3 nanophosphors were also studied. TL emission showed a strong green (545 nm) emission at ~400 K and a characteristic Sm3+ emission was observed at a high dopant concentration. The results obtained were favorable for the application of high dose gamma radiation dosimetry.

Lithium ions incorporated samarium doped yttrium oxide nanostructured thin films are prepared by spray pyrolysis. Glancing angle X-ray diffraction spectrum reveals the phase and crystallinity of the film. The crystallites sizes are found to be ∼50 nm. Surface morphology of the film is studied using field emission scanning electron microscope. The image appears as carved sculptures of particles with agglomeration. Fourier transformed infrared spectrum shows a sharp and wide absorption peak at 875 cm −1 . Optical absorption spectrum exhibits a prominent absorption peak at 270 nm and the corresponding energy gap is found to be ∼5.53 eV. A broad photoluminescence emission is observed in the range 560–690 nm with a peaks at 595, 608 and 622 nm and shoulders at 580, 645 and 662 nm. The films are irradiated with γ-rays in a dose range 187–563 Gy. Thermoluminescence glow curve is deconvoluted into three peaks with temperature maxima at 400, 460 and 580 K. The activation energy and frequency factor of these TL glows are found to be in the order of ∼0.58 eV and ∼10 6 s −1 respectively.

Sol gel derived nanocrystalline yttria pellets are irradiated with 120 MeV Ag 9+ ions for fluence in the range 1 × 10 12 –3 × 10 13 ions cm −2 . Pristine and irradiated samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. XRD pattern of pristine Y 2 O 3 nanocrystal reveal cubic structure. A new XRD peak at 30.36° is observed in pellet irradiated with 1 × 10 13 ions cm −2 . The peak at 30.36° is corresponding to ( 4 0 2 ¯ ) plane of monoclinic phase. The diffraction intensity of ( 4 0 2 ¯ ) plane increases with Ag 9+ ion fluence. Raman spectrum of pristine pellet show bands corresponding to cubic phase. And, ion irradiated sample show new peaks at 410, 514 and 641 cm −1 corresponding monoclinic phase. HR-TEM and SAED pattern of ion irradiated sample confirmed the presence of monoclinic phase. Hence, it is confirmed that, 120 MeV Ag 9+ ions induce phase transformation in nanocrystalline Y 2 O 3 .

Nanoparticles of Y2O3:Dy3+ were prepared by the solution combustion method. The X-ray diffraction pattern of the 900°C annealed sample shows a cubic structure and the average crystallite size was found to be 31.49 nm. The field emission scanning electron microscopy image of the 900°C annealed sample shows well-separated spherical shape particles and the average particle size is found to be in a range 40 nm. Pellets of Y2O3:Dy3+ were irradiated with 100 MeV swift Si8+ ions for the fluence range of 3 × 1011_3 × 1013 ions cm−2. Pristine Y2O3:Dy3+ shows seven Raman modes with peaks at 129, 160, 330, 376, 434, 467 and 590 cm−1. The intensity of these modes decreases with an increase in ion fluence. A well-resolved thermoluminescence glow with peaks at ∼414 K (Tm1) and ∼614 K (Tm2) were observed in Si8+ ion-irradiated samples. It is found that glow peak intensity at 414 K increases with an increase in the dopant concentration up to 0.6 mol% and then decreases with an increase in dopant concentration. Th...

Luminescence emission of lithium incorporated lanthanum doped yttrium oxide thin films are studied. The films were prepared by spray pyrolysis method at 375 ± 10 °C. The crystallites sizes were evaluated and found to be ~50 nm from the X-ray diffraction peak. The feature of surface morphology was obtained by field emission scanning electron microscope. Fourier transformed infrared spectrum represent absorption peak is at 875 cm−1. Optical absorption peak at 260 nm reveals the red shift in Li doped samples with energy gap 5.42 eV. Photoluminescence emissions are at 317, 390, 428 and 612 nm. Gamma-irradiated films shows TL glow peaks at 465 K and 588 K and their corresponding activation energies and the frequency factors were found to be 0.56 eV, 1.1 MHz and 0.6 eV, 0.3 MHz respectively. The incorporated Li ions played a vital role to decrease the processing temperature with the improved the morphological features.

Pure and Dy 3+ doped Y 2 O 3 are prepared by sol–gel technique. The samples are annealed at 900 °C to obtain crystalline phase. X-ray diffraction (XRD) patterns confirm cubic phase of Y 2 O 3 . The crystallites size is calculated using Scherrer formula and is found to be in the order of 29.67 nm. The particles are found to be spherical in nature and their sizes are estimated to be 35 nm by scanning electron microscope (SEM) technique. Online ionoluminescence (IL) spectra of pure and Dy 3+ doped Y 2 O 3 are recorded with 100 MeV Si 8+ ions with fluence in the range 0.375–6.75×10 13 ions cm −2 . Undoped samples do not show IL emission for any of the fluence explored. Four prominent IL emissions with peaks at 488, 670, 767 nm and a prominent pair at 574 and 584 nm are observed in Dy 3+ doped samples. These characteristic emissions are attributed to luminescence centers activated by Dy 3+ ions due to 4 F 9/2 → 6 H 15/2 , 4 F 9/2 → 6 H 11/2, 4 F 9/2 → 6 H 9/2 + 6 H 11/2 and 4 F 9/2 → 6 H 13/2 transitions respectively. Further, it is found that IL intensity at 574 nm decays rapidly with ion fluence. A broad and weak photoluminescence (PL) emission with peak at ~485 nm and a strong emission at 573 nm are observed in ion irradiated Y 2 O 3 :Dy 3+ . It is found that PL intensity increases with ion fluence up to 3×10 10 ions cm −2 and then it decreases with further increase of ion fluence. This may be attributed to lattice disorder produced by dense electronic excitation under swift heavy ion irradiation.

Lithium ion incorporated yttrium oxide thin films have been deposited by spray pyrolysis. The phase and crystalline nature of the thin film has been studied by glancing angle X-ray diffraction. Fourier transformed infrared spectroscopy reveal the broad and sharp absorption and found with peak 875 cm−1. Solid grains in nature are seen in the image of the thin film procured by the field emission-scanning electron microscopy. The energy gap of the thin film sample has been found through the UV–vis absorption studies and found its value is ∼5.37 eV. The photoluminescence emission spectrum was recorded under the excitation wavelength of 254 nm. Photoluminescence emission spectrum reveals the peaks are at 390, 485, 525 and 598–625 nm. Gamma irradiated thin films exhibits thermoluminescent glows with peaks at 460 and 538 K. The thermoluminescence glow curves are analyzed through glow curve shape method.

Nanocrystalline Nd3+ doped Y2O3 was synthesized by sol–gel technique. Crystallite size calculated by Scherrer relation was found to be in the range 28–30 nm. Fourier transform infrared spectroscopy (FTIR) revealed Y O, OH stretching and C O bending bonds. Pellets of Y2O3:Nd3+ were irradiated with 100 MeV swift Si8+ ions and γ-rays for the fluence/dose in the range 3 × 1011–3 × 1013 ions cm−2 and 1.0_14 kGy respectively. A prominent thermoluminescence (TL) glow with peak at 527 K and a weak one with peak at 600 K were observed in Si8+ ion irradiated samples while, a prominent TL glow with peak at 393 K besides a shoulder at 434 K and a weak one with peak at 581 K were observed in γ-irradiated phosphors. The relative TL efficiency of Y2O3:Nd3+ of 100 MeV Si ion beam to γ-rays of 60Co and is found to be 0.059. The TL kinetic parameters were calculated using Chen’s peak shape method and the results obtained are discussed. Y2O3:Nd3+ was observed for its use in space dosimetry application.

Nanocrystalline erbium doped yttrium oxide (Y2O3:Er 3+ ) was synthesized by the sol-gel technique using citric acid as complexing agent. The synthesized samples were characterized by X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM) techniques for phase-purity and microstructure. Er 3+ doped Y2O3 crystallizes in cubic phase with an average crystallite size of 24.3 nm. The pellets of Y2O3:Er 3+ were irradiated with 100 MeV swift Si 8+ ions with fluence in the range of 3×10 11 - 3×10 13 ions cm -2 . Three well resolved thermoluminescence (TL) glows with peaks at ~422, 525 and 620 K were observed in Er 3+ doped Y2O3 samples. It was observed that the TL intensity was found to increases with increasing Er 3+ concentration up to 0.4 mol% in Y2O3 and thereafter it decreases with further increase of Er 3+ concentration. Also, the intensity of low temperature TL glow peak (~422 K) increases with increasing ion fluence up to 1×10 12 ions cm

Lanthanum aluminate (LaAlO3) is synthesized by solution combustion method and the resultant powder is annealed at 900°C for 2 hours. X-ray diffraction (XRD) pattern confirms the rhombohedral structure LaAlO3 with space group R3¯c. γ-irradiated nanocrystalline lanthanum aluminate gives two prominent TL glow with peaks at 399 and 639 K and weak one at 547 K. TL intensity at 399 K increases up to 9.0 kGy and then decreases with increasing γ-dose. TL emission shows at 650 nm and 736 nm is attributed to the charge transfer from oxygen to metal ions. The glow curves are analyzed and the trap parameters are calculated by glow curve deconvoluted technique.Lanthanum aluminate (LaAlO3) is synthesized by solution combustion method and the resultant powder is annealed at 900°C for 2 hours. X-ray diffraction (XRD) pattern confirms the rhombohedral structure LaAlO3 with space group R3¯c. γ-irradiated nanocrystalline lanthanum aluminate gives two prominent TL glow with peaks at 399 and 639 K and weak one at 547 K. TL intensity at 399 K increases up to 9.0 kGy and then decreases with increasing γ-dose. TL emission shows at 650 nm and 736 nm is attributed to the charge transfer from oxygen to metal ions. The glow curves are analyzed and the trap parameters are calculated by glow curve deconvoluted technique.

Europium-doped yttrium oxide thin films have been deposited by a spray pyrolysis method. The crystallite sizes are calculated to be ~50 nm using Scherrer׳s formula. Fourier transformed infrared spectroscopy (FTIR) reveals broad absorption with peak at 875 cm −1 . Surface morphology and elemental composition of the thin films are studied by a field-emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray spectroscopy (EDS). The energy gap ( E g ) of the thin film sample is found to be ~5.37 eV. The film exhibits photoluminescence (PL) emission over 525–550 nm, 585–601 nm, 612 nm and 620–632 nm under the excitation of 240 nm. Gamma (γ)-irradiated films exhibit two well-resolved thermoluminescent (TL) glows with peaks at 460 and 570 K. The TL glow curves are analyzed by a glow curve shape method. The activation energy and the frequency factor are found to be, respectively, ~0.6 eV, ~3×10 6 s −1 for 460 K and ~0.53 eV, ~46.72×10 3 s −1 for 570 K.

Combustion synthesized Y 2 O 3 revealed cubic structure and the average crystallite size is found to be 32.73 nm. FTIR spectra revealed Y–O, OH stretching and C–O bending bonds. Y 2 O 3 pellets are irradiated with 100 MeV Si 8+ ions in the fluence range 1 × 10 10 to 1 × 10 14 ions cm −2 . PL of irradiated samples shows emission with peaks at 417, 432, 465 nm. Y 2 O 3 shows a prominent well resolved TL glow with peak at ∼403 K ( T m1 ) and a weak TL peak at 461 K ( T m2 ). TL intensity in the present work increases up to about 1 × 10 11 ions cm −2 there after it decreases. The TL kinetic parameters are calculated by glow peak shape method. Activation energy and frequency factors are found to in the range of ∼1.6 eV and ∼10 18 s −1 respectively.

Nanocrystalline yttrium aluminum garnet (Y3Al5O12) is synthesized by combustion technique. The X-ray diffraction (XRD) pattern of 900 °C annealed sample revealed a cubic structure. The average crystallite size is found to be 20.5 nm. γ-irradiated Y3Al5O12 exhibits two thermoluminescence (TL) glows: a prominent one with a peak at ∼410 K and another one with a peak at ∼575 K. It is found that the TL glow peak intensity at 410 K increases, while its glow peak temperature is almost steady with an increase in the γ-dose. The effect of the heating rate on the TL glow curve is studied. It is found that Tm1 shifts towards higher temperature region while the Im1 decreases with an increase in the heating rate. The TL glow curves are analyzed by Chen's peak shape method and the TL parameters are estimated.

Nanoparticles of pure yttrium oxide (Y 2 O 3 ) have been prepared by sol gel method. The powder X-ray diffraction (PXRD) pattern of as synthesized sample showed the amorphous nature. The as synthesized Y 2 O 3 powders are annealed at 500, 600, 700, 800 and 900 °C for 2 h. Y 2 O 3 powder heat treated for 600 °C showed cubic phase and the crystallite sizes are found to be ∼13 nm. Fourier transformed infrared spectroscopy (FTIR) revealed absorption with peaks at 3434, 1724, 1525, 1400, 847, 562 and 465 cm −1 . Photoluminescence (PL) of 100 MeV Si 8+ ion irradiated samples shows emission with peaks at 417, 432, 465 nm. It is found that PL intensity increases with increasing in ion fluence up to ∼3 × 10 12 ions cm −2 and then decreases with further increase in ion fluence. A well resolved thermoluminescence (TL) glow with peak at ∼430 K (Tm 1 ) and an unresolved TL glow with peak at ∼538 (Tm 2 ), 584 K (Tm 3 ) are observed in ion irradiated samples.

Optical absorption spectra of gamma irradiated (γ-rayed) Strontium (Sr) doped Calcium fluoride (CaF2) single crystals showed a prominent absorption peak at ∼370 nm and two weak ones at ∼463 and 524 nm. At higher γ-dose the two weak peaks merged into a broad one at ∼520 nm. The Photoluminescence (PL) spectra showed a prominent emission at ∼394 nm when the crystals were excited at ∼240 nm. The excitation of samples at 370 nm showed strong emission at ∼530 nm with a shoulder at ∼465 nm. The optical absorption and PL intensities were found to increase with γ-dose. However, the optical absorption and PL intensities of CaF2:Sr are found to be less than those of undoped CaF2 single crystals.

Nanocrystalline yttrium oxide (Y2O3) is synthesized by low temperature sol-gel technique and synthesized material is annealed at 900°C. The annealed β-rayed Y2O3 two TL glows with prominent peak at 407 K and weak glow peak at 643 K were observed in all irradiated samples. It is found that TL glow peaks intensity linearly increases with increase in β-dose from 0.813 – 40.625 Gy. The TL kinetic parameters are calculated using glow curve deconvoluted (GCD) method. The TL glows exhibits general order kinetics. Intense optical stimulated luminescence (OSL) is observed in the Y2O3 sample. These material exhibits linearity and reproducibility and hence, it suggests that this material may be used as dosimetric applications.

Europium doped Y2O3 nanophosphor has been prepared by solution combustion method. The obtained phosphors were characterized by powder x-ray diffraction (PXRD).It reveals that the cubic crystalline phase of the material with an average crystallite size of 21 nm. Photoluminescence (PL) excitation spectra of gamma irradiated nanophosphors were recorded under the emission wavelength of 611 nm. PL excitation spectra reveal the distinct peaks at 252, 301, 321, 396 and 466 nm. Meanwhile, PL emission peaks at 534, 552 – 592, 611, 629-645, 687 and 710 nm were observed for excitation wavelength of 252 nm. The excitation and emission spectra of irradiated sample exhibits low intensity compared that of un-irradiated sample and found that its intensity increases up to 4.0 kGy of gamma dose and then decreases with further increase of dosage.

Nanoparticles of Mg 2 SiO 4 :Eu 3+ have been prepared by the solution combustion technique and the grain size estimated by PXRD is found to be in the range 40–50 nm. Ionoluminescence (IL) studies of Mg 2 SiO 4 :Eu 3+ pellets bombarded with 100 MeV Si 8+ ions with fluences in the range 1.124–22.48×10 12 ions cm −2 are carried out at IUAC, New Delhi, India. Five prominent IL bands with peaks at 580 nm, 590 nm, 612 nm, 655 nm and 705 nm are recorded. These characteristic emissions are attributed to the luminescence centers activated by Eu 3+ cations. It is found that IL intensity decreases rapidly in the beginning. Later on, the intensity decreases slowly with further increase of ion fluence. The reduction in the ionoluminescence intensity with increase of ion fluence might be attributed to degradation of Si–O (ν 3 ) and Si–O (2ν 3 ) bonds present on the surface of the sample. The red emission with peak at 612 nm is due to characteristic emission of 5 D 0 → 7 F 2 of the Eu 3+ cations. Thermoluminescence (TL) studies of Mg 2 SiO 4 :Eu 3+ pellets bombarded with 100 MeV Si 8+ cations with fluences in the range 5×10 11 ions cm −2 to 5×10 13 ions cm −2 are made at RT. Two prominent and well resolved TL glows with peaks at ∼220 °C and ∼370 °C are observed. It is observed that TL intensity increases with increase of ion fluence. This might be due to creation of new traps during swift heavy ion irradiation.

Luminescence exhibiting europium doped yttrium oxide (Y 2 O 3 :Eu 3+ ) phosphor was prepared by solution combustion method, using disodium ethylene diamine tetra acetic acid (EDTA-Na 2 ) as fuel at ∼350 °C. Powder X-ray diffraction (PXRD) pattern of Y 2 O 3 :Eu 3+ revealed the cubic crystalline phase. The morphology of the samples was studied by scanning electron microscopy (SEM) and was foamy, fluffy and porous in nature. Fourier transformed infrared spectroscopy (FTIR) revealed prominent absorption with peaks at 3415, 1435, 875 and 565 cm −1 . Optical absorption studies showed the energy gap of the synthesized samples to be 5.4–5.5 eV. The photoluminescence (PL) of Y 2 O 3 :Eu 3+ exhibiting emission peak at 611 nm under the excitation of 254 nm. Thermoluminescence of γ-irradiated Y 2 O 3 :Eu 3+ showed two well resolved TL glows with peaks at 460 and 610 K and they were analyzed by glow curve shape method and the activation energies were found to be 0.421 eV and 1.016 eV respectively.

Magnesium (Mg) and Strontium (Sr) doped Calcium fluoride nanocrystals were synthesized by co-precipitation method. The cubic structure of the samples was confirmed by Powder X-ray diffraction. The average crystallite size of Mg doped samples was found to be ~ 25 nm whereas in Sr doped one it was ~ 35 nm. The morphological features revealed that the nanocrystals were agglomerated, crispy and porous. The as-prepared samples showed the presence of hydroxyl groups. The optical absorption spectrum of as-prepared Mg doped samples showed a strong absorption band peaked at ~ 233 nm whereas the Sr doped one showed a prominent absorption peak at 248 nm. A strong PL emission was observed at ~ 300 nm in Mg doped samples. However, the Sr doped samples showed two prominent emissions at ~ 345 and 615 nm.

Pure yttrium oxide (Y 2 O 3 ) was prepared by solution combustion technique using disodium ethylene diamine tetra acetic acid (EDTA-Na 2 ) as fuel at ~ 350 °C. Powder X-ray diffraction (PXRD) pattern of Y 2 O 3 revealed cubic crystalline structure with crystallite size in the range of 18–23 nm. The scanning electron microscopy (SEM) indicated the foamy and fluffy nature of the sample. Fourier transformed infrared spectroscopy (FTIR) revealed four prominent absorption with peaks at 3395, 1433, 875 and 566 cm − 1 . From the optical absorption studies the energy gap of the synthesized sample was found to be 5.72 eV. Two well resolved thermoluminescence (TL) glows with peaks at 475 and 626 K were observed in γ-irradiated Y 2 O 3 . The glow curves were analyzed and the average activation energy was found to be 0.505 and 0.977 eV respectively.

Samarium-doped calcium fluoride (CaF2) nanoparticles were synthesized by the co-precipitation method and characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), optical absorption and photoluminescence (PL) techniques. The PXRD patterns confirmed the cubic crystallinity of the synthesized nanoparticles. The average particle size estimated using Scherer's formula was ∼20 nm. The purity of the synthesized nanoparticles was confirmed by the FTIR spectrum. The morphological features studied using SEM revealed that the nanoparticles were agglomerated and porous. The optical absorption spectrum showed a strong and prominent absorption peak at ∼264 nm and a weak one at ∼212 nm. The PL spectrum showed broad and prominent emissions with peaks at ∼387 and 532 nm along with weak emissions at 573 and 605 nm.

Ionoluminescence (IL) of nano crystalline Mg 2 SiO 4 :Dy 3+ pellet samples bombarded with 100 MeV Si +8 ions with fluences in the range (1.124–22.480) × 10 12 ions cm −2 have been studied. Two prominent IL bands with peaks at ∼480 nm and ∼580 nm and a weak band with peak at ∼670 nm are recorded. The characteristic peaks are attributed to luminescence center activated by Dy 3+ ions due to the transitions 4 F 9/2 → 6 H 15/2, 6 H 13/2 and 6 H 11/2 . It is found that IL intensity initially decreases rapidly and then continuous to decrease slowly with further increase in ion fluence. The reduction in the Ionoluminescence intensity with increase of ion fluence might be attributed to degradation of Si–O ( 2 ν 3 ) bonds present on the surface of the sample and/or due to lattice disorder produced by dense electronic excitation under heavy ion irradiation.

Thermoluminescence (TL) of neodymium doped yttrium oxide (Y2O3:Nd3+) nanocrystalline phosphors, synthesized by solution combustion route, using disodium ethylene diamine tetra acetic acid (EDTA-Na2) as fuel, was studied at low temperature (

Nanoparticles of Eu 3+ doped Mg 2 SiO 4 are prepared using low temperature solution combustion technique with metal nitrate as precursor and urea as fuel. The synthesized samples are calcined at 800 °C for 3 h. The Powder X-ray diffraction (PXRD) patterns of the sample reveled orthorhombic structure with α-phase. The crystallite size using Scherer's formula is found to be in the range 50–60 nm. The effect of Eu 3+ on the luminescence characteristics of Mg 2 SiO 4 is studied and the results are presented here. These phosphors exhibit bright red color upon excitation by 256 nm light and showed the characteristic emission of the Eu 3+ ions. The electronic transition corresponding to 5 D 0 → 7 F 2 of Eu 3+ ions (612 nm) is stronger than the magnetic dipole transition corresponding to 5 D 0 → 7 F 1 of Eu 3+ ions (590 nm). Thermoluminescence (TL) characteristics of γ-rayed Mg 2 SiO 4 :Eu 3+ phosphors are studied. Two prominent and well-resolved TL glows with peaks at 202 °C and 345 °C besides a shoulder with peak at ∼240 °C are observed. The trapping parameters-activation energy ( E ) , order of kinetics ( b ) and frequency factor ( s ) are calculated using glow curve shape method and the results obtained are discussed.

Lanthanum-doped Calcium fluoride (CaF2) nanoparticles were synthesized by co-precipitation method and characterized by powder X-ray diffraction, Fourier infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), BET surface area measurements, and Optical absorption techniques. The X-ray diffraction pattern showed the cubic phase of fluorite structure. The average crystallite size was found to be ~25 nm. The FTIR spectrum showed the presence of hydroxyl groups in the as prepared sample with two strong IR absorption bands at ~3400 and 1550 cm−1. The morphological features studied by SEM revealed that nanoparticles were agglomerated. Surface area measurements showed porous nature of the nanoparticles. The optical absorption spectrum of γ-irradiated samples showed a prominent absorption peak at ~385 nm and two weak ones at ~218 and 533 nm. The optical absorption was found to increase with increase in γ-dose.

Pellets of nanocrystalline aluminum oxide synthesized by a combustion technique are irradiated with 120 MeV Au(9+) ions for fluence in the range 5 x 10(11)-1 x 10(13) ions cm(-2). Two photoluminescence (PL) emissions, a prominent one with peak at similar to 525 nm and a shoulder at similar to 465 nm are observed in heat treated and Au(9+) ion irradiated aluminum oxide. The 525 nm emission is attributed to F(2)(2+)-centers. The PL intensity at 525 nm is found to increase with increase in ion fluence up to 1 x 10(12) ions cm(-2) and decreases beyond this fluence. Thermoluminescence (TL) of heat-treated and swift heavy ion (SHI) irradiated aluminum oxide gives a strong and broad TL glow with peak at similar to 610 K along with a weak shoulder at 500 K. The TL intensity is found to increase with Au(9+) ion fluence up to 1 x 10(13) ions cm(-2) and decreases beyond this fluence. (C) 2010 Elsevier B.V. All rights reserved.

Pure and Ytterbium (Yb) doped Calcium fluoride (CaF2) single crystals were irradiated with 100 MeV Ni7+ ions for fluences in the range 5 × 1011–2.5 × 1013 ions cm−2. The irradiated crystals were characterized by Optical absorption (OA) and Thermoluminescence (TL) techniques. The OA spectra of ion irradiated pure CaF2 crystals showed a broad absorption with peak at ∼556 nm and a weak one at ∼220 nm, whereas the Yb doped crystals showed two strong absorption bands at ∼300 and 550 nm. From the study of OA spectra, the defect centers responsible for the absorption were identified. TL measurements of Ni7+ ion irradiated pure CaF2 samples indicated a strong TL glow with peak at ∼510 K. However, the Yb doped crystals showed two TL glows at ∼406 and 496 K. The OA and TL intensity were found to increase with increase of ion fluence upto 1 × 1013 ions cm−2 and thereafter it decreased with further increase of fluence. The results obtained are discussed in detail.

Calcium fluoride nanocrystals (CaF 2 ) were synthesized by two different techniques namely co-precipitation and hydrothermal. The synthesized nanocrystals were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared red spectroscopy (FTIR), scanning electron microscopy (SEM), optical absorption and photoluminescence (PL). The crystallite size estimated using Scherer's formula was found to be in the range 30–35 nm for nanocrystals synthesized by co-precipitation method where as in case of hydrothermally synthesized nanocrystals it is in the range 20–28 nm which is less compared to those obtained by co-precipitation method. The morphological features as studied using SEM revealed that the nanocrystals are agglomerated, crispy with porous. The SEM images of hydrothermally synthesized nanocrystals showed less agglomeration than those obtained by co-precipitation method and the images confirm the formation of nanoparticles. The optical absorption spectrum showed a strong absorption band peaked at 244 nm for nanocrystals synthesized by co-precipitation method and it is 218 nm peak in case of hydrothermally synthesized ones. The PL emission spectrum showed two prominent emission bands peaked at 330 and 600 nm when excited at 218 nm.

Ion irradiation induced phase transformation in calcite single crystals have been studied by means of Raman and infrared spectroscopy using 120 MeV Au9+ ions. The observed bands have been assigned according to group theory analysis. For higher fluence of 5×1012 ion/cm2, an extra peak on either side of the 713 cm−1 peak and an increase in the intensity of 1085 cm−1 peak were observed in Raman studies. FTIR spectra exhibit extra absorption bands at 674, 1589 cm−1 and enhancement in bands at 2340 and 2374 cm−1 was observed. This might be due to the phase transformation from calcite to vaterite. The damage cross section ( σ ) for all the Raman and FTIR active modes was determined. The increase of FWHM, shift in peak positions and appearance of new peaks indicated that calcite phase is converted into vaterite.

Polycrystalline aluminum oxide is synthesized by combustion technique and XRD studies of the sample revealed the α-phase. The synthesized sample is irradiated with 120 MeV swift Au9+ ions for the fluence in the range from 1 × 1011 to 1 × 1013 ions cm−2. A broad photoluminescence (PL) emission with peak at ∼ 447 nm and two sharp emissions with peak at ∼ 679 and ∼ 695 nm are observed in pristine when sample was excited with 326 nm. However, in the irradiated samples the PL intensity at ∼ 447, 679 and 695 nm decreases with increase in ion fluence. The α-Al2O3 gives rise to seven Raman modes with Raman intensity with peaks at ∼ 253, 396, 417, 546, 630, 842, 867 cm−1 observed in pristine. The intensity of these modes decreases with increase in ion fluence. However, the Raman modes observed at lower fluences are found to disappear at higher fluence.

The modifications of calcium sulphate (CaSO4·2H2O) single crystals are investigated by means of Raman and Fourier transform infrared spectroscopy (FT-IR) using 100 MeV Ag8+ ions in the fluence range 1 × 1011 to 5 × 1013 ions/cm2. It is observed that the intensities of the Raman modes decrease with increase in ion fluence. We determined damage cross-section (σ) for all the Raman active modes and found to be different for different Raman modes. Further, FT-IR studies have been carried out to confirm surface amorphisation for a fluence of 1 × 1013 ions/cm2. It is observed that the absorption peaks at 1132–1156 cm−1 corresponds to ν3(SO42−) mode. The decrease in Raman peaks intensity with ion fluence is attributed to degradation of ν3(SO42−) modes present on the surface of the sample.

We present the results of photoluminescence (PL) measurements on 100 MeV Ni(8+) ion irradiated Al(2)O(3) single crystals in the fluence range 1x10(11) to 5x10(12) ions/cm(2). A sharp PL peaks at approximately 693, 695, 707 and 730 nm are recorded with an excitation of 442 nm He-Cd laser beam. The sharp emission peaks at 693 and 695 nm are attributed to R(2) and R(1) lines of Cr(3+) ions, and they are related to the transition from (2)E(g)--(4)A(2g). The weaker sharp peaks called N lines appear at approximately 707 nm and its origin is ascribed due to closely coupled pairs of Cr(3+) ions. The longer wavelength part of the PL spectra at approximately 730 nm may be due to increase of groups of more than two Cr(3+) ions. It is observed that the broad emission band (450-650 nm) consists of four bands centered at 470, 518, 547 and 618 nm, respectively. The 470, 518 and 547 nm bands are corresponding to F(2)(+), F(2) and F(2)(2+) defect center, respectively. It is observed that the PL intensity of F(2), F(2)(2+), R and N lines increases with Ni(8+) ion fluence. This can be attributed to increase in concentration of color centers responsible for luminescence through radiative recombination.

Ionoluminescence (IL) of natural kyanite crystals was studied during 120 MeV Au9+ ion irradiation in the fluence range 1.50−12 × 1011 ions/cm2. The IL spectrum exhibits sharp peaks at ∼689, 694, 705, 713 and 716 nm, along with a broad emission peak at 530 nm recorded for all samples investigated. The sharp emission peaks at 689 and 694 nm are attributed to R2 and R1 lines of Cr3+ impurities, and they are related to the transition 2Eg → 4A2g. The peaks at 705–716 nm are attributed to Fe3+ impurities and are related to the transition 4T1g → 6A1g. It was observed that up to a given fluence, the IL peak intensity grows, reaches a maximum and gradually decreases with increase of Au9+ ion fluence. The decrease in IL intensity might be attributed to disorder produced by dense electronic excitation under swift heavy ion irradiation. The stability of the chemical species was studied both with and without irradiation by means of FTIR spectroscopy. The results confirm that the Si−O−Al, Al−O and Si−O (2ν3) type speci...

Raman and Infrared studies were carried out on pristine and 100 MeV Ag(8+) ion irradiated calcite single crystals in the fluence range 1 x 10(11) to 1 x 10(13)ions/cm(2). Raman and Infrared modes were assigned according to factor theory analysis. It is observed that the intensities of the Raman and infrared bands decrease with increase of ion fluence. The decrease of these bands is attributed to breakage of carbonate ions and other details are discussed.

Ionoluminescence (IL) of kyanite single crystals during 100 MeV Si8+ ion irradiation has been studied in the fluence range 1.87–7.50×1011 ions/cm2. Photoluminescence (PL) of similar dimensional crystals was recorded with same ions and energy in the fluence range 1×1011–5×1013 ions/cm2 with an excitation of 442 nm He–Cd laser beam. A sharp IL and broad PL peaks at ∼689 and 706 nm were recorded. This is attributed to luminescence centers activated by Fe2+ and Fe3+ ions. It is observed that up to a given fluence, the IL and PL peak intensities increase with increase of Si8+ ion fluence. The stability of the chemical species was studied on with and without irradiated samples by means of FT-IR spectroscopy. The results confirm that the O–Si–H type bonds covering on the surface of the sample. This layer might be acting as a protective layer and thereby reducing the number of non-radiative recombination centers.

Thermoluminescence (TL) of combustion-synthesized aluminum oxide bombarded with 120 MeV swift Au 9 + ions in the fluence range of 1 × 10 11 - 2 × 10 13 ions cm - 2 has been studied at room temperature. Two TL glows—a well-resolved one with peak at ∼ 623 K ( Tg 2 ) and another unresolved one at ∼ 513 K (Tg1)—are recorded at a heating rate of 10 K s - 1 . It is found that the TL intensity increases with the fluence up to 1 × 10 13 ions cm - 2 and then decreases with increase in fluence. Also, the prominent glow peak temperature ( Tg 2 ) is found to be shifted towards the lower temperature region, while the TL intensity increases with the increase in ion fluence. In the case of heat-treated samples, the TL intensity is observed to be enhanced further. However, in the case of samples heat-treated beyond 973 K, the TL intensity is found to be decreased with the increase in heat treatment. The glow curves are analyzed by the glow curve deconvolution technique and trap parameters are estimated and discussed in this paper.

Synthesis of materials by combustion technique results in homogeneous and fine crystalline product. Further, the technique became more popular since it not only saved time and energy but also was easy to process. Aluminum oxide phosphor was synthesized by using urea as fuel in combustion reaction. Photoluminescence (PL) and thermally stimulated luminescence (TSL) characteristics of γ-irradiated aluminum oxide samples were studied. A broad PL emission with a peak at ∼ 465 nm and a pair of strong and sharp emissions with peaks at 679 and 695 nm were observed in γ-rayed samples. The PL intensity was observed to increase with increase in γ-ray dose. Two prominent and well resolved TSL glows with peaks at 210°C and 365°C were observed in all γ-irradiated Al2O3 samples. The TSL intensity was also found to increase with increase in γ-ray dose. The TSL glow curves indicated second order kinetics.

Al2O3 thin films find wide applications in optoelectronics, sensors, tribology etc. In the present work, Al2O3 films prepared by electron beam evaporation technique are irradiated with 100 MeV swift Si7+ ions for the fluence in the range 1 × 1012 to 1 × 1013 ions cm−2 and the structural properties are studied by glancing angle X-ray diffraction. It shows a single diffraction peak at 38.2° which indicates the γ-phase of Al2O3. Further, it is observed that as the fluence increases up to 1 × 1013 ions cm−2 the diffraction peak intensity decreases indicating amorphization. Surface morphology studies by atomic force microscopy show mean surface roughness of 34.73 nm and it decreases with increase in ion fluence. A strong photoluminescence (PL) emission with peak at 442 nm along with shoulder at 420 nm is observed when the samples are excited with 326 nm light. The PL emission is found to increase with increase in ion fluence and the results are discussed in detail.

Ionoluminescence (IL) of kyanite single crystals bombarded with 100 MeV swift Ag8+ ions with fluences in the range 1.87–7.5×1011 ions/cm2 has been studied. A pair of sharp IL peaks at ∼689 and 706 nm along with broad emission in the region 710–800 nm are recorded in both crystalline and pelletized samples. Similar results are recorded in Photoluminescence (PL) of pelletized kyanite bombarded with same ions and energy with fluences in the range 1×1011–5×1013 ions/cm2 with an excitation of 442 nm laser beam. The characteristic pair of sharp emission peaks at 689 and 706 nm in both IL and PL is attributed to luminescence centers activated by Fe2+ and Fe3+ ions. The reduction in IL and PL bands intensity with increase of ion fluence might be attributed to degradation of Si–O (2ν3) bonds, present on the surface of the sample.

Aluminum oxide, a promising material for high temperature applications, is synthesized by combustion route and characterized by X-ray diffraction technique. Photoluminescence of aluminum oxide bombarded with 120 MeV swift Au9+ ions have been studied at room temperature. The observed PL emission with peak at ∼420 nm is attributed to F-center while the two more weak emissions with peaks at ∼482 and ∼525 nm are attributed to aggregates of F-centers. It is found that PL intensity increases with increase in Au9+ ion fluence up to ∼1×1013 ions cm−2 and thereafter it reaches saturation. The Fourier transform Infrared spectroscopy results show the destruction of Al‒O‒H bonds whereas the XRD results indicate the surface amorphization of Al2O3.

Thermoluminescence (TL) of kyanite single crystals bombarded with 100 MeV swift Ag 8+ and Si 8+ ions with fluences in the range 1 × 10 11 –5 × 10 14 ions/cm 2 has been studied at room temperature (RT). Two TL glows with peaks one at ∼445 K and another one at ∼550 K are recorded in Si 8+ ion bombarded kyanite single crystals at a warming rate of 20 K min −1 . It is observed that the TL peak intensity increases with increase of ion fluence. This may be attributed to the creation of new traps during bombardment process. However, in the case of Ag 8+ ion bombarded samples, a single well resolved glow with peak at ∼520 K is observed in all the samples. Also, photoluminescence (PL) of Ag 8+ ion irradiated kyanite single crystals have been studied and it is observed that a pair of sharp as well as strong PL emission bands with peaks at ∼688 and 706 nm along with a broad emission band in the region 710–800 nm at an excitation of 442 nm laser beam. It is found that PL intensity decreases with increase of ion fluence. The decrease in intensity with increase of ion fluence is attributed to amorphization of the sample.

Photoluminescence (PL) of pelletized mullite samples irradiated with 100 MeV swift Ni8+ ions with fluences in the range 1 × 1011–5 × 1013 ions/cm2 have been studied at RT. A broad and strong PL emission band with peak at ∼537 nm besides a sharp emission band with peak at ∼705 nm have been recorded in combustion synthesized mullite. However, a single broad emission with peak at ∼537 nm have been recorded in mullite synthesized by sol–gel technique at an excitation of 442 nm laser beam. It is found that PL intensity is decreases with increase of Ni8+ ion fluence. The decrease in PL intensity is attributed to destruction of Al–O and Si–O bonds in the samples. Infrared absorption (IR) studies of as it is and Ni8+ ion irradiated mullites have also been studied and results obtained are discussed.